Practice resources

* [Rabbithole](https://rabbithole.gg/)
* [Zapper](https://zapper.fi/)
* [Layer3](https://layer3.xyz/)

Explore Sidechains & Scaling Solutions

As you are getting deeper into the rabbit hole, it’s time to face some hot crypto problems. 

As the number of Ethereum users is growing, there are certain limitations in capacity, which result in slower and more expensive transactions (high gas cost). It’s hard to address these issues without sacrificing decentralization (and thus the security of the blockchain).

To dive deeper into the problem of scalability, you can read [this](https://ethereum.org/en/developers/docs/scaling/) article. Sidechains are explained [here](https://ethereum.org/en/developers/docs/scaling/sidechains/).

We’ll explore Polygon, Arbitrum and Optimism.

📚 Read more 📚

* Get to know Arbitrum and Optimism through [this video](https://youtu.be/7pWxCklcNsU)
* Polygon through [this video](https://youtu.be/IijtdpAtOt0)
* Comparison of all three solutions [here](https://morioh.com/p/8ede541f6252)

For the purpose of this exercise, the first thing that we’ll need to do is to add new (Custom RPC) networks to the Metamask. [Here](https://metamask.zendesk.com/hc/en-us/articles/360043227612-How-to-add-a-custom-network-RPC) is a guide on how to do that.

In order to transfer assets from one chain to another, we usually use different blockchain [bridges](https://coinmarketcap.com/alexandria/article/what-are-blockchain-bridges). These transactions (when moving from Layer 1 Ethereum mainnet) can be expensive due to the high gas cost, so you don’t need to try them on your own in this tutorial. Instead, you will use the assets that you already have on Polygon from our previous exercise “Get your first crypto”.

If you want to explore bridges on your own, a user guide on bridging the assets from Ethereum to Polygon can be found [here](https://consensys.net/blog/metamask/how-to-bridge-tokens-from-ethereum-to-polygon-with-metamask/). 

Here are the links to different bridge solutions:

* [Polygon Web Wallet](https://wallet.polygon.technology) with the bridge functionality
* [Arbitrum bridge](https://bridge.arbitrum.io)
* [Optimism bridges](https://www.optimism.io/apps/bridges)

Practice:

1. Move part of your assets that we withdrew from Binance through previous exercise from Polygon to Arbitrum using the [Hop Exchange](https://hop.exchange)
2. Move part of your assets to Optimism (again using the Hop Exchange)
3. Try [1inch](https://app.1inch.io) on all three networks
4. Try [Uniswap](https://app.uniswap.org) on Arbitrum and Optimism
5. Try [Quickswap](https://quickswap.exchange) on Polygon