Limit Internet access until your child makes progress on educational sites(dnslearning.org)
dnslearning.org
Limit Internet access until your child makes progress on educational sites
https://dnslearning.org/
57 comments
As a kid who actually used to boot from linux, delete the "internet security product" from program files, and then happily access the internet, I think it's a great idea, to train your kids to always find solutions.
When I was in school I found that the content blocking only monitored the actual page you were visiting, so if you wanted to go to albinoblacksheep.com or whatever, you just wrote an HTML page with an iframe inside and it would work fine.
Memories...
Memories...
When I was in school Internet wasn't a thing yet.
However, me and some friends "hacked" the program that blocked virtually everything interesting unless you had the password on our school computers. The first thing we did was boot up in DOS. There we found the secret password file for the blocking program. Alas, when we tried the password it didn't work. It must be encrypted! So we went back into DOS and renamed the password file. When we booted up Windows again the program thought it was running for the very first time and asked us to enter a password. We entered "AAAAAA" and exited into DOS again. The new password file now contained the "encrypted" password: "GGGGGG". Hmm, there's a pattern here... We then restored the old password file and "decrypted" the original password. From that point on we had full access to any system! Those were the days!
However, me and some friends "hacked" the program that blocked virtually everything interesting unless you had the password on our school computers. The first thing we did was boot up in DOS. There we found the secret password file for the blocking program. Alas, when we tried the password it didn't work. It must be encrypted! So we went back into DOS and renamed the password file. When we booted up Windows again the program thought it was running for the very first time and asked us to enter a password. We entered "AAAAAA" and exited into DOS again. The new password file now contained the "encrypted" password: "GGGGGG". Hmm, there's a pattern here... We then restored the old password file and "decrypted" the original password. From that point on we had full access to any system! Those were the days!
That's incredibly witty. Props to you.
For kids like that we suggest segmenting them into their own router. They can still install a VPN, unless you use our Android app (which is a VPN itself, and you can't have two active in Android at once)
If you were already booted to Linux, why tamper with the Windows partition at all? You might just as well have accessed the 'net with Linux.
If the software was blocking at a lower level on the network stack and not just in the browser, then the answer is probably multiplayer games. Presumably OP wasn't doing this just last year, but in the late 90s and early 2000s when Linux gaming wasn't a real thing yet.
Correct. It still isn't tbh.
Thinking on the kid's side. I personally don't want to be a kid who is forced to learn something which I have no interest in. Especially to get access to the internet on my free time to do/learn something that interests me.
Reinforced learning will give results, but better results can be obtained if the `desire` to learn is developed from within.
Reinforced learning will give results, but better results can be obtained if the `desire` to learn is developed from within.
I honestly think the desire to learn something is not something that exists inside us, but rather develops based on how we are appreciated the first few times we try to learn something.
Can't fathom how kids can be interested or not in things they have no experience with.
Can't fathom how kids can be interested or not in things they have no experience with.
It seems to me the opposite: kids are born with a natural curiosity of the world around them, which is why at a young age they incessantly ask the question "why?". This quickly becomes annoying to the adults, who were themselves taught not to ask so many questions, and so the cycle repeats.
Big brother-esque/authoritarian programs such as this which enforce arbitrary learning boundaries kill the natural curiosity and spontaneity of the child because it forces them into a mold rather than fostering a genuine interest.
Big brother-esque/authoritarian programs such as this which enforce arbitrary learning boundaries kill the natural curiosity and spontaneity of the child because it forces them into a mold rather than fostering a genuine interest.
I disagree. The desire to learn is always within us it is the very nature of human being.
It is very observable among kids. They try to learn everything by observing around them. Limiting the window to which they can learn is what the conventional school system has implemented through ages.
I cannot find the point in forcing a kid to learn math when he is clearly interested in music or art. At best he will become a bad mathematician. Where he could have become a great musician. The idea of forcefully planting interest of something inside a young mind is terrible.
Instead, give him the freedom to choose. Give his both math and art. Let him choose what he likes.
And please don't give a reward if he chooses math over music.
It is very observable among kids. They try to learn everything by observing around them. Limiting the window to which they can learn is what the conventional school system has implemented through ages.
I cannot find the point in forcing a kid to learn math when he is clearly interested in music or art. At best he will become a bad mathematician. Where he could have become a great musician. The idea of forcefully planting interest of something inside a young mind is terrible.
Instead, give him the freedom to choose. Give his both math and art. Let him choose what he likes.
And please don't give a reward if he chooses math over music.
There are multiple educational sites supported by this tool, but indeed they are focused on math just because that is the most common. Can you recommend any sites or apps teaching the subjects you warned might be left out?
Teachers and technologies that make learning fun and appealing are definitely best. This tool is intended more to provide limits against going too far in the opposite direction.
If you have any recommendations on how to purposefully develop a desire for learning in others (especially children), I would appreciate it if you would be willing to take the time to share them!
If you have any recommendations on how to purposefully develop a desire for learning in others (especially children), I would appreciate it if you would be willing to take the time to share them!
On a tangential note: I am still waiting for a philanthropic billionaire to create (sponsor) the ultimate learning digital world for kids of all ages (in 200+ languages please) aka Ready Player One.
There are already some high-quality learning apps (reading and counting) for kids but the best ones are paid and they usually cover only a narrow segment in a narrow subject.
I wonder if the "authorities of Effective Altruism" would agree with me that this is a good way to spend charity money.
There are already some high-quality learning apps (reading and counting) for kids but the best ones are paid and they usually cover only a narrow segment in a narrow subject.
I wonder if the "authorities of Effective Altruism" would agree with me that this is a good way to spend charity money.
I hands down agree with you. However, authorities of Effective Altruism on other hand are focused more on what is perceived by the world as efficient damage control on a large scale.
The ultimate learning digital world for kids might not be possible considering the diversity in our world. Also, I doubt authorities look at the current learning environment as damaging.
The ultimate learning digital world for kids might not be possible considering the diversity in our world. Also, I doubt authorities look at the current learning environment as damaging.
You may be overestimating the diversity in our world - consider what percentage of world kids population is exposed to the unifying experience of Bollywood, Nollywood, Hollywood, Pop Music, K-pop, WoW, LoL, memes. I would argue that kids all over the world are very similar these days.
Do you have any pointers to recommended technologies for kids to learn foreign languages?
Please only in one language but with a really good course for that language as the first material.
English would be nice, but I would also accept lojban or hawaiian.
English would be nice, but I would also accept lojban or hawaiian.
I'm really curious as to why you'd only want our mythical billionaire to build it just in one language?
Computer science is an amazing field to work in because we all communicate and collaborate in english, it makes large scale global project efforts possible.
I would like to see that hurdle removed from other disciplines.
Same goes for international politics and peace, your neighbour becomes a lot less threatening if you speak the same language.
German is my mother tounge but after living in the netherlands for 4 years, I consider english my primary language, its what I write my grocery lists and diary entries in. I think the world would be a much better place if we all spoke the same language.
Also f* unicode. That unmaintainable mess of a standard. ASCII4ever!
I would like to see that hurdle removed from other disciplines.
Same goes for international politics and peace, your neighbour becomes a lot less threatening if you speak the same language.
German is my mother tounge but after living in the netherlands for 4 years, I consider english my primary language, its what I write my grocery lists and diary entries in. I think the world would be a much better place if we all spoke the same language.
Also f* unicode. That unmaintainable mess of a standard. ASCII4ever!
See... I'm a native English speaker, and while a lot of things would be easier if we all spoke the same language, I think the world would be a poorer place because of it. There's so much more to language than just the words - it seems to alter the way you think too.
My partner is Dutch, and I love that there are words like "papegaaiduiker" the word for puffin. Translates as "parrot diver". I think it'd be totally sad if things like that died out. I suspect if our mythical system existed, it would quickly make English the only language about.
With you on ASCII ;)
My partner is Dutch, and I love that there are words like "papegaaiduiker" the word for puffin. Translates as "parrot diver". I think it'd be totally sad if things like that died out. I suspect if our mythical system existed, it would quickly make English the only language about.
With you on ASCII ;)
When your child is 3-4, you don't necessarily want to start with a foreign language, especially if the parents don't speak English. Think of all the languages supported by your favorite tablet.
Or maybe you are right - I am sure learning experts will know what is the right thing to do.
Or maybe you are right - I am sure learning experts will know what is the right thing to do.
I don't think it's a good idea, "well used" (and setting what is or what is not a good use on the application of this might be kind of hard) can be an incentive for the childs, but, an overuse of this/using it as an obligation might cause the counter effect of associating learning with obligation and with that, the contempt towards learning, or having it as something negative that hinders what child want to get.
".org" domain suggests (to me, at least) that this is a free service, however, it won't stay free.
There is no information about how it works, let alone some technical aspects - interesting, especially considering the name. About link doesn't work as well.
There is no information about how it works, let alone some technical aspects - interesting, especially considering the name. About link doesn't work as well.
We are a registered non-profit but yes we have to keep our monetization options open.
I will fix the About link.
We are a small team and marketing isn't our forte so any feedback or suggestions are appreciated.
I will fix the About link.
We are a small team and marketing isn't our forte so any feedback or suggestions are appreciated.
Appreciate the feedback - a 'how it works' is a great idea, especially for the HN audience.
Thanks also for the tip on the About link!
Thanks also for the tip on the About link!
> DnsLearning is Free until January 2018
Oh wow, literally.
Oh wow, literally.
I hope nobody will try to use this as a substitute for supervision with regards to children accessing the internet. Not that many parents seem to think supervision is necessary for children accessing the internet, which never fails to floor me.
For what it's worth we block many bad domains and soon will be forcing YouTube into restricted mode (by always resolving to restricted.youtube.com CNAME records)
I have to admit I thought this app design through before and think it's a great idea. I have wished to see an app like this and have tried other nanny style apps but found that they eventually break and can be bypassed.
My question to the developers is are you using undocumented APIs for core functionality and what is being done to ensure that future android updates don't kill core functions that make the system work.
My question to the developers is are you using undocumented APIs for core functionality and what is being done to ensure that future android updates don't kill core functions that make the system work.
To avoid bypassing we have a iOS app on the way their APIs allow for parental controls.
For Android you have to use a device that has support for restricted profiles.
We don't do anything undocumented to prevent bypassing and we have actually taken some bypass protection features out while we fine tune our UI and onboarding experience.
For Android you have to use a device that has support for restricted profiles.
We don't do anything undocumented to prevent bypassing and we have actually taken some bypass protection features out while we fine tune our UI and onboarding experience.
To the best of my knowledge, the bulk of the restrictions are implemented by pointing devices to a custom DNS server (a VPN can accomplish much the same but I don't know if this product implements that). The majority of the app is the user interface for the reporting/status capabilities. You can read a bit more about the implementation on the HN discussion where I discovered this tool: https://news.ycombinator.com/item?id=14913547
> utefan001: After 30 min, DNS no longer works for entertainment sites. [...] It takes her 5 to 7 mins to earn points. My server detects points and re enables DNS replies for YouTube
The somewhat similar Circle product is sold as a device that resides on the local network and accomplishes its configuration using ARP poisoning.
> utefan001: After 30 min, DNS no longer works for entertainment sites. [...] It takes her 5 to 7 mins to earn points. My server detects points and re enables DNS replies for YouTube
The somewhat similar Circle product is sold as a device that resides on the local network and accomplishes its configuration using ARP poisoning.
Hi Timothy,
We have designed DnsLearning so that all you need to do is point the child's device to use one of our DNS servers and then link an education site. As long as a device supports changing DNS, the device will always work. The play/app stores are not our main focus.
Hi guys I'm a developer on this project if you have any questions or notice something that could be improved please tell me here or [email protected]
Thank you all!
Thank you all!
Hi,
I don't see a privacy policy or other page which makes it clear what information you collect and how that information is stored.
How is session management handled from the point of view of administering the service, how does the service track users and for how long is that information stored?
I don't see a privacy policy or other page which makes it clear what information you collect and how that information is stored.
How is session management handled from the point of view of administering the service, how does the service track users and for how long is that information stored?
I would appreciate hearing more about what it would take to satisfy your privacy concerns. DNS providers do gain a 99.9%+ complete overview (and VPN providers get complete metadata) into the browsing habits of their users, and it is more than reasonable to request a public commitment documenting how this information is handled.
In general there is an entire category of the majority of users who don't care enough about their privacy, and then a second group who want to know that it's been considered but appreciate the convenience of relying on a third party. (I think the Signal app is good example of a tool attempting to cater to these first two categories.)
A slightly overlapping but mostly separate third group is not going to be satisfied by just about anything a third party claims to do (often in part due to nation-state level considerations) and typically doesn't use off-premises tools like this one. It is hard to justify attempting to meet the needs of this small but vocal group of users since it reduces the level of convenience (and thus mass-market appeal) that can be offered to the other groups.
It is, however, very much worth documenting where the line is drawn because doing so can alleviate legitimate concerns of the privacy-conscious but busy second group and avoid public outcry (caused by speculation/proof of incompetence and/or indifference) being picked up by the majority of potential users.
In general there is an entire category of the majority of users who don't care enough about their privacy, and then a second group who want to know that it's been considered but appreciate the convenience of relying on a third party. (I think the Signal app is good example of a tool attempting to cater to these first two categories.)
A slightly overlapping but mostly separate third group is not going to be satisfied by just about anything a third party claims to do (often in part due to nation-state level considerations) and typically doesn't use off-premises tools like this one. It is hard to justify attempting to meet the needs of this small but vocal group of users since it reduces the level of convenience (and thus mass-market appeal) that can be offered to the other groups.
It is, however, very much worth documenting where the line is drawn because doing so can alleviate legitimate concerns of the privacy-conscious but busy second group and avoid public outcry (caused by speculation/proof of incompetence and/or indifference) being picked up by the majority of potential users.
We added a privacy policy:
https://dnslearning.org/privacy
The wording isn't perfect yet and we have to be careful how we say things, but we don't sell any data to a third party. We don't use Google Analytics either or anything like that.
We automatically delete the data after 30 days and we actually have this implemented so the user can decide how long they want data to be kept, but when I cleaned up the UI the ability for users to modify this setting got lost.
https://dnslearning.org/privacy
The wording isn't perfect yet and we have to be careful how we say things, but we don't sell any data to a third party. We don't use Google Analytics either or anything like that.
We automatically delete the data after 30 days and we actually have this implemented so the user can decide how long they want data to be kept, but when I cleaned up the UI the ability for users to modify this setting got lost.
Regarding how long the information is stored. We are going to add a feature that allows you to configure how long the domain history is stored.
Just added this..https://dnslearning.org/privacy
Just noticed that is says "We haven't seen your phone or table yet!" on https://dnslearning.org/timeline, I'm assuming that should be tablet?
Thanks!
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@@ -30,7 +30,7 @@
<td colspan="3">
<p class="text-center">
<p class="text-center">
- We haven't seen your phone or table yet!
+ We haven't seen your phone or tablet yet!
</p>
</p>
</td>I think there needs to be more information present on the site - the about/home page doesn't show anything other than the most cursory information, and I think you'd want a lot more than that to convince most people to try it.
I may give it a whirl this weekend with my kids, but I'll see how it goes. The issue with most of these strategies is that kids are generally good penetration testers in their own (limited) way; if one means of accessing the internet is blocked, they'll use another one; given that they have access to different devices and no universal management system, I think they will just flip to another device.
Don't get me wrong, I think things like this are a useful tool in the arsenal of a parent who cares about their child's upbringing. I always find it slightly depressing when I see comments such as "this isn't a replacement for being a real parent", etc., which always seem to come with the subtext of [like i am] to them. I don't think anyone who would care about this sort of thing would think it was a replacement. I'm a step-parent to 4 kids (18,16,13,11) and it is a difficult task to get them onside in terms of what I see as responsible internet usage (which increasingly comes down to not only time, but the kind of sites and apps they are using), and most importantly what's easiest referred to as 'screen time' - games, etc. As mentioned above, if you do manage to lock something down in terms of time, then they'll use something else. And I really care about this, but it's a difficult thing to police in terms of actual effort, attention and also expectations. I don't think it's healthy for them to spend all their time on any kind of device, so we go out for walks and do activities when we can, and Sunday afternoon until Monday breakfast is no devices for ANYONE at all (Us included, which has been a real success after the initial resentment and whining), but often real life or work gets in the way, and having a way of enforcing limits of usage or actively promoting worthwhile usage to gain credits for trivial use would be a good thing to do, IMO.
But I'm yet to see anything which comes close to doing it; I did have a router running Gargoyle a few years ago, with each device in an appropriate group, and times enforced, but it couldn't handle that many reservations and crashed enough to make it more trouble than it's worth. That's compounded by the older kids having their own phones with some (limited) data plan, which can of course get round any restrictions. Promoting a 'stop using your device an hour before you go to bed' can be wearing, no matter how good your intentions, and how pleasant the kids may be.
In short, unless there's a universal standard for this, and everyone signs up to it (across all manufacturers and devices), I think it will have limited success, alas.
I may give it a whirl this weekend with my kids, but I'll see how it goes. The issue with most of these strategies is that kids are generally good penetration testers in their own (limited) way; if one means of accessing the internet is blocked, they'll use another one; given that they have access to different devices and no universal management system, I think they will just flip to another device.
Don't get me wrong, I think things like this are a useful tool in the arsenal of a parent who cares about their child's upbringing. I always find it slightly depressing when I see comments such as "this isn't a replacement for being a real parent", etc., which always seem to come with the subtext of [like i am] to them. I don't think anyone who would care about this sort of thing would think it was a replacement. I'm a step-parent to 4 kids (18,16,13,11) and it is a difficult task to get them onside in terms of what I see as responsible internet usage (which increasingly comes down to not only time, but the kind of sites and apps they are using), and most importantly what's easiest referred to as 'screen time' - games, etc. As mentioned above, if you do manage to lock something down in terms of time, then they'll use something else. And I really care about this, but it's a difficult thing to police in terms of actual effort, attention and also expectations. I don't think it's healthy for them to spend all their time on any kind of device, so we go out for walks and do activities when we can, and Sunday afternoon until Monday breakfast is no devices for ANYONE at all (Us included, which has been a real success after the initial resentment and whining), but often real life or work gets in the way, and having a way of enforcing limits of usage or actively promoting worthwhile usage to gain credits for trivial use would be a good thing to do, IMO.
But I'm yet to see anything which comes close to doing it; I did have a router running Gargoyle a few years ago, with each device in an appropriate group, and times enforced, but it couldn't handle that many reservations and crashed enough to make it more trouble than it's worth. That's compounded by the older kids having their own phones with some (limited) data plan, which can of course get round any restrictions. Promoting a 'stop using your device an hour before you go to bed' can be wearing, no matter how good your intentions, and how pleasant the kids may be.
In short, unless there's a universal standard for this, and everyone signs up to it (across all manufacturers and devices), I think it will have limited success, alas.
Thanks for checking us out! There is an international standard for this, DNS. Devices before 1987 are not supported (RFC 1035).
With regards to device hopping, try getting a spare router and setting it up then changing the Wifi password so kids only have access to the single router. Some routers will also enforce DNS packets (so even if they modify the DNS in their phone or tablet it will not work)
I agree we are not a replacement for parenting in general. We are a tool. We think parents want to be better at managing this but don't have the tools to do it. Even the best solutions available we could find require setting strict schedules or constantly being pestered to turn a site on or off.
Also we provide the ability to modify how long they get access for. It defaults to 30 minutes right now, but I would suggest setting it higher if you think they will put up a fight. What I have seen (even with myself) is virtually any amount of time limit will eventually invoke the "Why am I watching this?" effect since you value the time more if you work for it.
With regards to phones we have an Android app right now and are in the process of finishing our iOS app. Both platforms support installing an app that requires flashing the phone back to stock to disable it. We have tested this on both platforms but not yet enabled it since it complicates things and we are still getting what we have working. Also our apps are a VPN itself, and you cannot have multiple VPNs enabled on either platform. While we currently only use our Layer 2 control in the VPN to enforce DNS settings in the future we can do a lot more.
With regards to device hopping, try getting a spare router and setting it up then changing the Wifi password so kids only have access to the single router. Some routers will also enforce DNS packets (so even if they modify the DNS in their phone or tablet it will not work)
I agree we are not a replacement for parenting in general. We are a tool. We think parents want to be better at managing this but don't have the tools to do it. Even the best solutions available we could find require setting strict schedules or constantly being pestered to turn a site on or off.
Also we provide the ability to modify how long they get access for. It defaults to 30 minutes right now, but I would suggest setting it higher if you think they will put up a fight. What I have seen (even with myself) is virtually any amount of time limit will eventually invoke the "Why am I watching this?" effect since you value the time more if you work for it.
With regards to phones we have an Android app right now and are in the process of finishing our iOS app. Both platforms support installing an app that requires flashing the phone back to stock to disable it. We have tested this on both platforms but not yet enabled it since it complicates things and we are still getting what we have working. Also our apps are a VPN itself, and you cannot have multiple VPNs enabled on either platform. While we currently only use our Layer 2 control in the VPN to enforce DNS settings in the future we can do a lot more.
Any feedback on the website, sign-up flow, and especially the project itself would be tremendously appreciated.
When enabling the study sites it's not immediately clear the credentials should be for an account you create on that site. Safari just happily autofills them with login pair to dnslearning itself. Perhaps "create account here" link to signup pages (where possible) would be helpful.
I wish there were some experimental evidence that this approach is effective. Would some parental attention and tutoring have the same effect as the "educational sites"?
Speaking as a parent to now teenager.
Fact is just like their parents, kids are tremendously connected these days, so there's a massive networking effect in the cohort. There's much less outdoor/social activities among kids than there were couple decades ago, simply because there's noone playing outside. Yes we can argue that no screen can replace human interaction fully but it does replace quite a bit of it.
We often hear this parents not doing their jobs sentiment over and over, either from people who have no kids or had them prior to smartphone era. Do you often find yourself spending a whole evening with a laptop or tablet? Checking facebook on your phone compulsively? Well same thing with kids. Sure I could just seize my son's devices, but then what? Push him out to the empty street? Try to be his playmate until he's 18? Because it's not just your kid, the whole social interaction fabric went the way of Great Barrier Reef.
Sure no technology can substitute parenting; most parents we know do the expected job of taking the kids for activities, courses, helping with homework etc. But you can't (and shouldn't) hover over your kids all the time. If this project can convert any of the social media/gaming time to at least something useful, it is priceless.
Fact is just like their parents, kids are tremendously connected these days, so there's a massive networking effect in the cohort. There's much less outdoor/social activities among kids than there were couple decades ago, simply because there's noone playing outside. Yes we can argue that no screen can replace human interaction fully but it does replace quite a bit of it.
We often hear this parents not doing their jobs sentiment over and over, either from people who have no kids or had them prior to smartphone era. Do you often find yourself spending a whole evening with a laptop or tablet? Checking facebook on your phone compulsively? Well same thing with kids. Sure I could just seize my son's devices, but then what? Push him out to the empty street? Try to be his playmate until he's 18? Because it's not just your kid, the whole social interaction fabric went the way of Great Barrier Reef.
Sure no technology can substitute parenting; most parents we know do the expected job of taking the kids for activities, courses, helping with homework etc. But you can't (and shouldn't) hover over your kids all the time. If this project can convert any of the social media/gaming time to at least something useful, it is priceless.
Regarding parental attention, the reality is that most parents are extremely busy. Single parents, long commutes, multiple jobs, etc. DnsLearning was primarily created to help parents that cannot afford private schools, tutoring, or moving out of a low income neighborhood. All of these great education sites are competing with very powerful algorithms that are designed to keep users watching video after video. If youtube starts encouraging users to do a few Khan Academy problems before watching the next video, I will consider DnsLearning a total success.
Hi Drallison, I am the co-creator. This is my biased description...
My 14 year old son said that he was surprised to learn how fast 30 mins goes by when using DnsLearning. Encouraging children to come up for air every 30 mins is a good thing. My 9 year old daughter went to Khan Academy 7 times one day during the summer. This means she was watching a lot of youtube videos. I told her I was impressed how many times she went to Khan Academy. She responded. "Yea, well I got tired of doing Khan Academy so I decided to clean my room instead." So, for those 2 cases, for my 2 children, it has been effective :)
I agree! However, that takes real work & prioritization (time) rather than electricity/technology.
Also (meme-ing a bit here): why not both? :)
In reality, it's always a mistake to let the nonexistent perfect be the enemy of the good (or to be most pessimistic: the not-as-bad).
I personally am desperate for an app-ified version of this well-researched "direct instruction" book/process: https://www.amazon.com/Teach-Your-Child-Read-Lessons/dp/0671...
Also (meme-ing a bit here): why not both? :)
In reality, it's always a mistake to let the nonexistent perfect be the enemy of the good (or to be most pessimistic: the not-as-bad).
I personally am desperate for an app-ified version of this well-researched "direct instruction" book/process: https://www.amazon.com/Teach-Your-Child-Read-Lessons/dp/0671...